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6 HEALTH AND LABORATORY MAGAZINE

NEW TYPE OF MAGNETIC

WAVE DISCOVERED ACROSS

EARTH’S OUTER CORE

Scientists have discovered a completely
new type of magnetic wave that sweeps

across the outermost part of Earth’s outer
core every seven years.

While volcanic eruptions solar storms can damage only real way of probing magnetic field from in- to buoyancy plumes. Each
and earthquakes serve as communication networks deep down to Earth’s core. struments based on the wave is specified by its
immediate reminders that and navigation systems Seismology and mineral surface of Earth suggested period and typical length-
Earth’s interior is anything and satellites, so while we physics provide informa- that there was some kind scale, and the period
but peaceful, there are can’t do anything about tion about the material of wave action, but we depends on characteristics
also other, more elusive, changes in the magnetic properties of the core, but needed the global cover- of the forces at play. For
dynamic processes taking field, understanding this they do not shed any light age offered by measure- magneto-Coriolis waves,
place deep down below invisible force helps us to on the dynamo-generating ments from space to reveal the period is indicative of
our feet. Using information be prepared. motion of the liquid outer what is actually going on. the intensity of the mag-
from ESA’s Swarm satellite core. netic field within the core.
mission, scientists have Most of the field is gen- “We combined satel-
discovered a complete- erated by an ocean of But now, using data from lite measurements from “Our research suggests
ly new type of magnetic superheated, swirling the Swarm mission, sci- Swarm, and also from the that other such waves are
wave that sweeps across liquid iron that makes up entists have unearthed a earlier German Champ likely to exist, probably with
the outermost part of Earth’s outer core 3000 hidden secret. mission and Danish Ørsted longer periods – but their
Earth’s outer core every km (1900 miles) under mission, with a computer discovery relies on more
seven years. This fascinat- our feet. Acting like the A paper, published in the model of the geodyna- research.”
ing finding, presented to- spinning conductor in a journal Proceedings of mo to explain what the
day at ESA’s Living Planet bicycle dynamo, it gener- the National Academy of ground-based data had ESA’s Swarm mission
Symposium, opens a new ates electrical currents and Sciences, describes how a thrown up – and this led to scientist, Ilias Daras, noted,
window into a world we can the continuously changing team of scientists detected our discovery.” “This current research is
never see. electromagnetic field. a new type of magnetic certainly going to improve
wave that sweeps across Owing to Earth’s rota-
Earth’s magnetic field is ESA’s Swarm mission, the ‘surface’ of Earth’s out- tion, these waves align in the scientific model of
the magnetic field within
like a huge bubble protect- which comprises three er core – so where the core columns along the axis of
ing us from the onslaught identical satellites, meas- meets the mantle. This rotation. The motion and Earth’s outer core. It may
of cosmic radiation and ures these magnetic sig- mysterious wave oscillates magnetic field changes also give us new insight
charged particles carried nals that stem from Earth’s every seven years and associated with these into the electrical conduc-
by powerful winds that es- core, as well as other propagates westward at waves are strongest near tivity of the lowermost part
cape the Sun’s gravitation- signals that come from the up to 1500 kilometers (900 the equatorial region of the of the mantle and also of
al pull and stream across crust, oceans, ionosphere, miles) a year. core. Earth’s thermal history.”
the Solar System. Without and magnetosphere.
our magnetic field, life as Nicolas Gillet, from the Uni- While the research exhibits Reference: “Satellite mag-
we know it could not exist. Since the trio of Swarm versity Université Grenoble magneto-Coriolis waves netic data reveal interan-
satellites was launched in Alpes and lead author of near seven-year period, nual waves in Earth’s core”
Understanding exactly how 2013, scientists have been the paper, said, “Geophys- the question of the exist- by Nicolas Gillet, Felix Ger-
and where our magnetic analyzing their data to gain icists have long theorized ence of such waves that ick, Dominique Jault, Tobias
field is generated, why new insight into many of over the existence of such would oscillate at different Schwaiger, Julien Aubert
it fluctuates constantly, Earth’s natural processes, waves, but they were periods, however, remains. and Mathieu Istas, 21
how it interacts with solar from space weather to the thought to take place over March 2022, Proceedings
wind, and, indeed, why it physics and dynamics of much longer time scales Dr. Gillet added, “Magnet- of the National Academy
is currently weakening, Earth’s stormy heart. than our research has ic waves are likely to be of Sciences.
is not only of academic shown. triggered by disturbances
interest but also of benefit Measuring our magnetic deep within the Earth’s DOI: 10.1073/
to society. For example, field from space is the “Measurements of the fluid core, possibly related pnas.2115258119